From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E09CC433EF for ; Tue, 24 May 2022 14:54:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238429AbiEXOyD (ORCPT ); Tue, 24 May 2022 10:54:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237325AbiEXOyB (ORCPT ); Tue, 24 May 2022 10:54:01 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BB7A56EC46 for ; Tue, 24 May 2022 07:53:59 -0700 (PDT) Received: from dggpemm500023.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4L6xyK0pg3zhYTq; Tue, 24 May 2022 22:52:57 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 24 May 2022 22:53:55 +0800 Received: from [10.174.177.243] (10.174.177.243) by dggpemm500001.china.huawei.com (7.185.36.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 24 May 2022 22:53:55 +0800 Message-ID: Date: Tue, 24 May 2022 22:53:54 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Subject: Re: [PATCH v3 4/6] mm: ioremap: Add arch_ioremap/iounmap() Content-Language: en-US To: Arnd Bergmann CC: Catalin Marinas , Will Deacon , Andrew Morton , Linux ARM , Linux Kernel Mailing List , Linux-MM , "Christoph Hellwig" , Anshuman Khandual References: <20220519082552.117736-1-wangkefeng.wang@huawei.com> <20220519082552.117736-5-wangkefeng.wang@huawei.com> <4c848b48-6ddf-664a-6296-d85ab49a694d@huawei.com> From: Kefeng Wang In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/5/24 22:47, Arnd Bergmann wrote: > On Tue, May 24, 2022 at 4:32 PM Kefeng Wang wrote: >> On 2022/5/24 20:37, Arnd Bergmann wrote: >>> On Thu, May 19, 2022 at 10:25 AM Kefeng Wang wrote: >>>> Add special hook for architecture to verify or setup addr, size >>>> or prot when ioremap() or iounmap(), which will make the generic >>>> ioremap more useful. >>>> >>>> arch_ioremap() return a pointer, >>>> - IS_ERR means return an error >>>> - NULL means continue to remap >>>> - a non-NULL, non-IS_ERR pointer is directly returned >>>> arch_iounmap() return a int value, >>>> - 0 means continue to vunmap >>>> - error code means skip vunmap and return directly >>>> >>>> Signed-off-by: Kefeng Wang >>> I don't really like interfaces that mix error pointers and NULL pointer >>> returns. >>> >>> Would it be possible to have a special error code other than NULL >>> for the fallback case? >> I don't find a good error code, maybe ENOTSUPP, any better suggestion? > I had another look at the resulting arm64 function, and it appears that > you never actually return a non-error pointer here. If I didn't miss anything, > I think the best way would be to change the return type to just indicate > success or an error code, and drop the case of returning the actual result, > and changing the function name accordingly. > > Would that work, or do you actually require returning an __iomem > token from somewhere else? Christoph  suggested in the first version, https://lore.kernel.org/linux-arm-kernel/Ymq2uX%2FY15HlIpo7@infradead.org/ > Arnd > > . From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 92C80C433EF for ; Tue, 24 May 2022 14:55:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:CC:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=s0F7PXQjzbmkEzC1jnLLku7chkKmdT9iOYDj+S+EJfU=; b=p3iZ21oh+qHkVS WkTkRE1YcF2hR7kFYPBvPzAdMcD4V3byrLqAdYNN8VmSpfaHCKb/2wGDkzXIGcr/3hWlQeAZietaL LdQMbor83cgjVu0WJJF6ZBCkH22wF14WkmNs1SeMIsrV/nyd/wlNvKZNBuysnUcYDx7HFWkhYAZwO KqFk/P353ATnxjzDxIqH8rZGmmvTuR83MJbwb5Za0wPfcVuD771B83ANlAFBEt+h7RsjfPRet82dB k6p3f5ZGt5M3j+dw01FujSEDon+pgMFOuo3dq/FGdfg0Lh0Ro6uW4Hrgu97jt9DYMsKv2607eGDqw P19zTDy83MmWG599HNSg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ntVvE-008KdK-Cw; Tue, 24 May 2022 14:54:08 +0000 Received: from szxga02-in.huawei.com ([45.249.212.188]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ntVvA-008Kax-MD for linux-arm-kernel@lists.infradead.org; Tue, 24 May 2022 14:54:06 +0000 Received: from dggpemm500023.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4L6xyK0pg3zhYTq; Tue, 24 May 2022 22:52:57 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 24 May 2022 22:53:55 +0800 Received: from [10.174.177.243] (10.174.177.243) by dggpemm500001.china.huawei.com (7.185.36.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 24 May 2022 22:53:55 +0800 Message-ID: Date: Tue, 24 May 2022 22:53:54 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Subject: Re: [PATCH v3 4/6] mm: ioremap: Add arch_ioremap/iounmap() Content-Language: en-US To: Arnd Bergmann CC: Catalin Marinas , Will Deacon , Andrew Morton , Linux ARM , Linux Kernel Mailing List , Linux-MM , "Christoph Hellwig" , Anshuman Khandual References: <20220519082552.117736-1-wangkefeng.wang@huawei.com> <20220519082552.117736-5-wangkefeng.wang@huawei.com> <4c848b48-6ddf-664a-6296-d85ab49a694d@huawei.com> From: Kefeng Wang In-Reply-To: X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220524_075404_947122_44445AE3 X-CRM114-Status: GOOD ( 14.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Ck9uIDIwMjIvNS8yNCAyMjo0NywgQXJuZCBCZXJnbWFubiB3cm90ZToKPiBPbiBUdWUsIE1heSAy NCwgMjAyMiBhdCA0OjMyIFBNIEtlZmVuZyBXYW5nIDx3YW5na2VmZW5nLndhbmdAaHVhd2VpLmNv bT4gd3JvdGU6Cj4+IE9uIDIwMjIvNS8yNCAyMDozNywgQXJuZCBCZXJnbWFubiB3cm90ZToKPj4+ IE9uIFRodSwgTWF5IDE5LCAyMDIyIGF0IDEwOjI1IEFNIEtlZmVuZyBXYW5nIDx3YW5na2VmZW5n LndhbmdAaHVhd2VpLmNvbT4gd3JvdGU6Cj4+Pj4gQWRkIHNwZWNpYWwgaG9vayBmb3IgYXJjaGl0 ZWN0dXJlIHRvIHZlcmlmeSBvciBzZXR1cCBhZGRyLCBzaXplCj4+Pj4gb3IgcHJvdCB3aGVuIGlv cmVtYXAoKSBvciBpb3VubWFwKCksIHdoaWNoIHdpbGwgbWFrZSB0aGUgZ2VuZXJpYwo+Pj4+IGlv cmVtYXAgbW9yZSB1c2VmdWwuCj4+Pj4KPj4+PiAgICAgYXJjaF9pb3JlbWFwKCkgcmV0dXJuIGEg cG9pbnRlciwKPj4+PiAgICAgICAtIElTX0VSUiBtZWFucyByZXR1cm4gYW4gZXJyb3IKPj4+PiAg ICAgICAtIE5VTEwgbWVhbnMgY29udGludWUgdG8gcmVtYXAKPj4+PiAgICAgICAtIGEgbm9uLU5V TEwsIG5vbi1JU19FUlIgcG9pbnRlciBpcyBkaXJlY3RseSByZXR1cm5lZAo+Pj4+ICAgICBhcmNo X2lvdW5tYXAoKSByZXR1cm4gYSBpbnQgdmFsdWUsCj4+Pj4gICAgICAgLSAwIG1lYW5zIGNvbnRp bnVlIHRvIHZ1bm1hcAo+Pj4+ICAgICAgIC0gZXJyb3IgY29kZSBtZWFucyBza2lwIHZ1bm1hcCBh bmQgcmV0dXJuIGRpcmVjdGx5Cj4+Pj4KPj4+PiBTaWduZWQtb2ZmLWJ5OiBLZWZlbmcgV2FuZyA8 d2FuZ2tlZmVuZy53YW5nQGh1YXdlaS5jb20+Cj4+PiBJIGRvbid0IHJlYWxseSBsaWtlIGludGVy ZmFjZXMgdGhhdCBtaXggZXJyb3IgcG9pbnRlcnMgYW5kIE5VTEwgcG9pbnRlcgo+Pj4gcmV0dXJu cy4KPj4+Cj4+PiBXb3VsZCBpdCBiZSBwb3NzaWJsZSB0byBoYXZlIGEgc3BlY2lhbCBlcnJvciBj b2RlIG90aGVyIHRoYW4gTlVMTAo+Pj4gZm9yIHRoZSBmYWxsYmFjayBjYXNlPwo+PiBJIGRvbid0 IGZpbmQgYSBnb29kIGVycm9yIGNvZGUsIG1heWJlICBFTk9UU1VQUCwgYW55IGJldHRlciBzdWdn ZXN0aW9uPwo+IEkgaGFkIGFub3RoZXIgbG9vayBhdCB0aGUgcmVzdWx0aW5nIGFybTY0IGZ1bmN0 aW9uLCBhbmQgaXQgYXBwZWFycyB0aGF0Cj4geW91IG5ldmVyIGFjdHVhbGx5IHJldHVybiBhIG5v bi1lcnJvciBwb2ludGVyIGhlcmUuIElmIEkgZGlkbid0IG1pc3MgYW55dGhpbmcsCj4gSSB0aGlu ayB0aGUgYmVzdCB3YXkgd291bGQgYmUgdG8gY2hhbmdlIHRoZSByZXR1cm4gdHlwZSB0byBqdXN0 IGluZGljYXRlCj4gc3VjY2VzcyBvciBhbiBlcnJvciBjb2RlLCBhbmQgZHJvcCB0aGUgY2FzZSBv ZiByZXR1cm5pbmcgdGhlIGFjdHVhbCByZXN1bHQsCj4gYW5kIGNoYW5naW5nIHRoZSBmdW5jdGlv biBuYW1lIGFjY29yZGluZ2x5Lgo+Cj4gV291bGQgdGhhdCB3b3JrLCBvciBkbyB5b3UgYWN0dWFs bHkgcmVxdWlyZSByZXR1cm5pbmcgYW4gX19pb21lbQo+IHRva2VuIGZyb20gc29tZXdoZXJlIGVs c2U/CgpDaHJpc3RvcGjCoCBzdWdnZXN0ZWQgaW4gdGhlIGZpcnN0IHZlcnNpb24sCgpodHRwczov L2xvcmUua2VybmVsLm9yZy9saW51eC1hcm0ta2VybmVsL1ltcTJ1WCUyRlkxNUhsSXBvN0BpbmZy YWRlYWQub3JnLwoKPiAgICAgICAgIEFybmQKPgo+IC4KCl9fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fCmxpbnV4LWFybS1rZXJuZWwgbWFpbGluZyBsaXN0Cmxp bnV4LWFybS1rZXJuZWxAbGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5mcmFkZWFk Lm9yZy9tYWlsbWFuL2xpc3RpbmZvL2xpbnV4LWFybS1rZXJuZWwK